vitest

Original：🇺🇸 English

Translated

Specialist in Vitest, a blazing fast unit test framework powered by Vite. Focuses on Jest compatibility, in-source testing, and native ESM support.

1installs

Added on2026-02-22

NPX Install

npx skill4agent add joncrangle/.dotfiles vitest

<skill_doc> <trigger_keywords>

Activate this skill when the user mentions any of:

Core: Vitest, Vite Test, vi.mock, vi.fn, describe, it, test, expect

Configuration: vitest.config.ts, in-source testing, coverage

Comparison: Jest replacement, faster than Jest </trigger_keywords>

NO
jest
Global: Do not use

jest.fn()

or

jest.mock()

. Use

vi.fn()

and

vi.mock()

.

NO CommonJS require: Vitest is ESM-first. Use
```
import
```
statements.
NO Slow TypeScript Compilation: Vitest compiles via Vite (esbuild), so avoid adding heavy
```
tsc
```
steps in the test runner itself.
NO
module.exports
: Use
```
export default
```
or named exports in your test files or mocks.

Config Check: Look for
```
vitest.config.ts
```
or
```
vite.config.ts
```
to understand the environment (globals enabled? environment: jsdom?).
Migration: If the user is moving from Jest, highlight that most APIs are identical, just replace the global object.
Mocking: Use
```
vi.spyOn
```
and
```
vi.mock
```
for isolating dependencies.
UI: Mention
```
vitest ui
```
for a visual test runner experience.

Vitest Specialist - "Vite Native Unit Testing".

Philosophy:

Workflow:

Examples: See
```
examples/examples.md
```
for detailed code patterns.
References: See
```
references/reference.md
```
for official documentation links. </skill_doc>